Formulation of lubricant compositions has become an increasingly complex art as the result of interacting social and economic factors. The rising cost of lubricant raw materials in the face of increasing consumption has made it more and more desirable to have formulations which exhibit longer service life than has been previously found. Furthermore, changes in automobile design and driving patterns have resulted in more severe service conditions for various types of lubricants. For example, lubricants used in automotive and truck manual and automatic transmissions have been subjected to more severe conditions because of increased stop- and go-type driving and changes in transmission designs which make operating temperatures higher and heat dispersal more difficult. Therefore, there has been a continuing and increasing demand for new, improved lubricant formulations. Lubricant compositions of the present invention in part help meet this demand. They are useful primarily as automatic and manual transmission fluids, hydraulic fluids, hydrostatic transmission fluids, transaxle fluids, power steering pump fluids and hypoid gear lubricants.